'Interfering' BT Vision attracts campaigner glares

Campaigners complaining about interference generated by BT's Vision product have financed independent tests to show that the kit BT is pushing fails to conform to the appropriate EU standards, prompting a complaint to trading standards officers.

Shortwave radio users have been complaining for a while about interference generated by networking over mains wiring, with BT taking the majority of the flak, but until now the protestors have been complaining to Ofcom on the basis of illegal broadcasting. By demonstrating that retailers are selling kit that fails to meet EU standards the protestors could prevent its sale, not to mention the possibility of fines for those manufacturing or importing the kit.

The kit provided by BT utilises powerline telecommunications (PLT) to connect components over mains wiring, but mains wiring is unshielded and therefore the house electrical system acts as a huge antenna generating radio signals that can interfere with low-frequency radio users nearby. Radio hams have set up a protest group to argue against the technology, and provide videos demonstrating the extent of the problem:

The only recourse for the aggrieved ham is reporting to Ofcom, who reckon they've received around 40 such complaints while estimating that 500,000 PLT devices are in operation in the UK. Ofcom also 'points out that they are powerless to act as long as the kit conforms to the appropriate standards and carries CE Mark attesting to that conformance.

But several members of the protest group, UKQRM, have now lodged complaints with Trading Standards on the basis of independent tests carried out by Hursley EMC. These show that devices manufactured by Comtrend, and supplied by BT, do not conform to EN55022 - the standard to which conformance is required.

Given the test results it would appear that the equipment could only be used if reserved frequencies were avoided - a process known as "notching" - but as UKQRM explains, the number of notches needed would reduce the bandwidth available over main wiring enough to make the technology uncompetitive.

But that's not relevant to Trading Standards, who will only be interested to know if someone is importing kit bearing a CE Mark that doesn't conform to the appropriate regulations. We contacted BT and Comtrend for comment, but BT just told us that it ensures goods bear the appropriate marks, while Comtrend haven't got back to us. ®